The proposed investigations continue ongoing efforts since inception of the Center to clarify the role of neurocognitive processes, specifically the executive cognitive functions(ECF), on the liability for a DSM-IV substance use disorder(SUD). Research conducted to date has shown that ECF capacity discriminates high average risk (HAR) from low average risk (LAR) youth ascertained on the basis of presence/absence of SUD in the proband father. In addition, emerging data indicate that ECF capacity in late childhood may bean important factor, albeit comparatively unstudied, influencing adolescent substance use (age 16) and the transition to SUD by young adulthood (age 19). In the forthcoming five year period, research in the Neurocognition Module will be extended to clarify the impact of ECF on SUD liability and its developmental course in relation to sexual maturation and environmental adversity. As a putativeSUD liability phenotype, the familial transmissibilityof ECF capacitywill also be determined .In as much as at least 107 male subjects in the sample are expected to transition to SLID by 22 years of age, CEDAR's longitudinal paradigm is uniquely positioned to determine the contribution of neurocognitive processes on the origins and pathways to SUD.